Dynamic and AI forecast models are shifting an upper trough into the East during the week 2-3 ahead period. CFS V2 lingers the trough in week-4 while ECM and AI models regenerate a Northeast U.S. ridge at that time. Climate Impact Company recognizes optimum climate normal (OCN) when potential pattern change is forecast in the extended range.

The Climate Impact Company U.S. selected cities CDD forecast shifted hotter in this week’s update and is close to the 2022 and 2024 observations. Summer of 2022 ranked 3rd hottest on record for the U.S. while summer 2024 ranked 4th hottest. The observed summer 2025 CDD will rival the 2022 and 2024 heat primarily due to the anomalous heat observed in the PJM sector.

Neutral or weak ENSO events do not imply low skill climate forecasts. Recognizing the new mid-latitude (mostly warm) SSTA regimes can not only foreshadow climate patterns ahead but also recognize the potential for extreme events such as heatwaves, droughts, and flooding rainfall episodes.

An interesting comparison between ECM "weeklies" and the AI GFS ENS 2-4-week temperature anomaly forecast for Australia whereas there is agreement on the upper air pattern (which supports increasing risk of cold in July) and AI GFS ENS offers the cold while ECM "weeklies" doubts the cold risk.